It's hard to speak about such things rationally when the only thing you present is biased hyperbole.
A "fair trial" is a luxury reserved for people that do not maim, torture, and systematically exterminate people for as little as holding them up while making a turn at an intersection. Once you start doing that, the gloves come off for the sake of each and every one of us. If you get raided and blitzed and don't make it to your trial after fighting back, I don't fucking care.
This isn't a conversation about "gamgs" of police officers. It's simply a conversation about "gamgs." Once you use the same terms to describe police officers as you do the Maras, or the Bloods, or Crips, or the LKN, or whatever "gamg" you would prefer to let live on to terrorize another neighborhood for another day, you lose all credibility you ever could have had in this conversation.
Police officers are not criminals simply because the pick up a badge and a gun. They do not live and breathe waiting for their moment to kill an innocent person. Those that do should be and are being weeded out of service, one way or another, and while the judicial system is pathetic in this country at convicting cops when they do wrong, the vast, vast majority of cops couldn't stomach the thought of hurting someone that doesn't deserve it. They do, though, live and breathe for opportunities to take out an organization that regularly threatens the lives of the people they swear to protect and serve. When one of those opportunities arises, by all means, they should be perfectly entitled to take it.
Since you have obviously never lived in, visited, or even seen an area that is plagued by gang violence, you should be aware that "gamgs of police officers" patrolling the streets sounds like a dream. In most of these neighborhoods, there is already a massive police presence, as there should be, but they concentrate their efforts into certain spaces. It's sort of like a farmer's market in Jerusalem - there's someone in uniform with a gun, because it's a setting with a lot of people, but is that necessarily going to help? No - maybe it's just going to move the action somewhere else. See a McDonalds? There's gonna be a cop there. Headed to school in the morning? Oh yeah, there's gonna be a few cops there, and there's gonna be a bucket at the office for students to toss their switchblades in, you know, since now they have police protection from the rampant gang violence. On the street, though? No. There are police, and they may patrol the streets, but their goal each and every morning is to play damage control, not to stop the problem. They don't engage with the community, they don't have the opportunity to catch criminals in the act, and they don't take down the people who run the whole show. This is where the problem lies with our enforcement of gangs in the first place. Having boots on the ground and people who can do what they need to do in order to protect the people that they are responsible for protecting would be the first major step in stopping the violence and reengaging law enforcement officers who have forgotten just how badly their community needs them and members of the community who have forgotten just how helpful law enforcement can be when they are allowed to fulfill their responsibilities.